
import java.util.Scanner;
public class Average {
    public static void main(String[] args) {
        Scanner console=new Scanner(System.in);
        double sum=0;
        int count=0;
        while (true){
            int number=console.nextInt();
            if(number==0){
                break;
            }
            sum+=number;
            count++;

        }
        System.out.printf("平均%.2f%n",sum/count);
    }

}
